I have four 8ohm and two 16ohm drivers. They are going to be my new home theater! I'm still working out which tweeter to buy. The cabinets are in homage to the 47labs design. Wide, tall and shallow. They are covered in cherry and the baffles are curly redwood. They are not done yet but I will post some pics this coming week.
nate
nate
WR125 Project Nearly Completed
Folks:
I know it has been a long time since I've updated this thread, but I finally found the time to engineer a crossover for the WR125S and DX19 in a Parts Express .25 cu ft enclosure.
The tweeter is mounted slightly off axis and I used a baffle diffraction simulator to determine the "optimal" baffle location for the tweeter.
I used SpeakerWorkshop to perform all my measurements (impedance and frequency response) I ended up with a 2nd order x-over on the woofer and a 1st order crossover on the tweeter. I have a somewhat minimilistic approach to x-over design. It was my goal to keep the parts count and cross over orders as low as possible.
The woofer x-over uses impedance correction circuitry to reduce the rise in impedance with increasing frequency. The tweeter uses impedance correction tuned to the tweeter's resonance frequency.
Tweeter polarity is reversed to avoid a rapid swing in phase response and a negative impact to the frequency response. The frequency response testing I performed, with the woofer mounted in it's final position, on the baffle and installed in the enclosure, showed a big dip centered around 5K in the woofer's output and a lot of extra energy in the 8-10K region. Initial testing indicates that the second order x-over combined with the impedance correction does a good job of subduing the extra energy above 8K and provides a smooth roll-off in overall response above 5K.
Since the woofer has output up so high, I was able to begin the tweeter roll-off at a fairly high frequency (somewhere around 10K).
Listening to the speaker I can state that it sounds very balanced, natural, detailed yet easy to listen to and has tremendous off-axis response and imaging.
I need to finish testing and tweaking, but once complete, I think this design will definitely be a winner. I would be willing to share my design if there is interest.
Regards,
Andrew
Folks:
I know it has been a long time since I've updated this thread, but I finally found the time to engineer a crossover for the WR125S and DX19 in a Parts Express .25 cu ft enclosure.
The tweeter is mounted slightly off axis and I used a baffle diffraction simulator to determine the "optimal" baffle location for the tweeter.
I used SpeakerWorkshop to perform all my measurements (impedance and frequency response) I ended up with a 2nd order x-over on the woofer and a 1st order crossover on the tweeter. I have a somewhat minimilistic approach to x-over design. It was my goal to keep the parts count and cross over orders as low as possible.
The woofer x-over uses impedance correction circuitry to reduce the rise in impedance with increasing frequency. The tweeter uses impedance correction tuned to the tweeter's resonance frequency.
Tweeter polarity is reversed to avoid a rapid swing in phase response and a negative impact to the frequency response. The frequency response testing I performed, with the woofer mounted in it's final position, on the baffle and installed in the enclosure, showed a big dip centered around 5K in the woofer's output and a lot of extra energy in the 8-10K region. Initial testing indicates that the second order x-over combined with the impedance correction does a good job of subduing the extra energy above 8K and provides a smooth roll-off in overall response above 5K.
Since the woofer has output up so high, I was able to begin the tweeter roll-off at a fairly high frequency (somewhere around 10K).
Listening to the speaker I can state that it sounds very balanced, natural, detailed yet easy to listen to and has tremendous off-axis response and imaging.
I need to finish testing and tweaking, but once complete, I think this design will definitely be a winner. I would be willing to share my design if there is interest.
Regards,
Andrew
Timn8ter said:
http://www.us.alegriaaudio.com/Ling.htm
http://www.rawacoustics.ca
http://www.creativesound.ca/details.php?model=KIT41
All these designs are very similar, but with different tweeters and/or HF crossovers. I've ordered the Raw Acoustics version (RAW-1F), with no tweeter. Here's my plan... You fine speaker makers are forgiven for laughing at my Frankenstein design. Any advice is welcomed:
I have a Marchand XM44-3, a pair of Rocket UFW10 subs, a pair of Usher 9950's and a pair of Energy 22 Ref Con speakers. The plan is to sit the RAW-1F cab on top of the Energy cab, secured with blu-tack. I think the size and colour (piano-black on matte black) will make this visually acceptable, and the Energy cabinet is double-thick wall, so it should be a decent support. The Usher will be mounted in place of the Energy tweeter.
Crossovers will be 60 Hz and 250 Hz (2nd-order). I'm not sure how to cross over to the tweeter, since neither the tweeter nor the RAW-1F is here yet. That's why I'm interested in Andrew's spec.
Andrew that is an unusual combination of 2nd order on woofer and 1st on tweeter, so you are thinking outside the box!
I would like to see any measurements that you have taken- particularly off axis. I was going to use the WR125 "naked" for my center channel but for my mains I was going to go full boat with tweeter, and active crossover to a pair of woofers. However, maybe re-think and put that tweeter in the center speaker as well if it really improves off-axis highs and doesn't mess with voice intelligibility .
Are you using that 2 way for your center now?
I like the idea of a compact cabinet for the speaker, but what about the baffle step? Your cab must have a drop off in response between 800hz and 200hz . Do you just use your receivers bass control to boost?
I would like to see any measurements that you have taken- particularly off axis. I was going to use the WR125 "naked" for my center channel but for my mains I was going to go full boat with tweeter, and active crossover to a pair of woofers. However, maybe re-think and put that tweeter in the center speaker as well if it really improves off-axis highs and doesn't mess with voice intelligibility .
Are you using that 2 way for your center now?
I like the idea of a compact cabinet for the speaker, but what about the baffle step? Your cab must have a drop off in response between 800hz and 200hz . Do you just use your receivers bass control to boost?
Combining orders
A lot of designers refuse to combine crossover orders, but I find that it's an effective design tool. It's especially handy in mid-tweet interfaces, if you get a mid that has a smooth rolloff and sounds good near the rolloff, you can use the acoustic response in conjunction with a lower-order XO to get a steep slope with fewer parts, and then use a higher order tweeter xo. It's all a function of designing around the driver, not coming up with an abstract design goals and expecting the drivers to sound good in what configuration *you* say they should. Flexible design will lead to better results than trying to force drivers to behave the way you want.
A lot of designers refuse to combine crossover orders, but I find that it's an effective design tool. It's especially handy in mid-tweet interfaces, if you get a mid that has a smooth rolloff and sounds good near the rolloff, you can use the acoustic response in conjunction with a lower-order XO to get a steep slope with fewer parts, and then use a higher order tweeter xo. It's all a function of designing around the driver, not coming up with an abstract design goals and expecting the drivers to sound good in what configuration *you* say they should. Flexible design will lead to better results than trying to force drivers to behave the way you want.
Re: Combining orders
That would lead to a first or second-order on the mid-woofer and a third or fourth-order on the tweeter. I thought that was a fairly common design? Second-order on the woofer and first-order on the tweeter as Andrew is suggesting sounds unusual to me (novice that I am).
badman said:
That would lead to a first or second-order on the mid-woofer and a third or fourth-order on the tweeter. I thought that was a fairly common design? Second-order on the woofer and first-order on the tweeter as Andrew is suggesting sounds unusual to me (novice that I am).
I was looking the infinate baffle frequency graph on zaphaudio and correct me if I am wrong, but does it seem like this driver has baffle step compensation already built in? It seem up about 4 or 5 db in the bass range.......which would be toned down in an enclosure, correct?
Am I right in saying the driver does not really need a baffle step correcting circuit like most do?
Am I right in saying the driver does not really need a baffle step correcting circuit like most do?
I've read this thread a couple of times and come up with an idea that I'd like some feedback on. Usually I know enough about audio to be dangerous, but when it comes to designing speakers, I know just enough to appear stupid. Be gentle. What I'd like to do is use two WR125STs(16 ohm version) in a small enclosure like the RAW-1F(there appears to be enough room for this due to the cutoff on the diameter of the mounting flange). I would like to mount a tweeter at the acoustic center on the top of the cabinet(weather the cabinet will be used vertically or horizontally will be determined after listening tests). I would like the enclosure volume to maximise linearity to 80hz, and then fall off as steeply as possible as I will be using a sub for frequencies below 80hz. My questions are 1. At what frequency will comb filtering effects start to set in, assuming the 125s are right next to each other? (This will determine the crossover point) 2. As the RAW enclosure is 12" tall and 7.5" wide, how deep would the enclosure need to be to get the best linearity to 80hz? Correct me if I'm wrong but a sealed enclosure will yield a steeper rolloff than a ported enclosure. 3. Would stuffing the enclosure with cotton or fiberglass, and putting a pressure release vent(aperiodic loading) be enough of a compensation to purhaps use the stock RAW cabinet(10" deep) to achieve the loading I am looking for? Thanks in advance for your responses.
Use a .5 cu ft cabinet. With the truncated frames comb filtering is going to be minimal enough to be a non-issue. I did a TL with them and the results were excellent.
http://www.us.alegriaaudio.com/Rosa.htm
I really need to do something about that picture.
http://www.us.alegriaaudio.com/Rosa.htm
I really need to do something about that picture.
Thanks for the input. I dont like the bi-pole idea at all as I've had experience with planars and while the sound is captivating and exciting initially ultimately its too much of a hassle to get realistic imaging. Everything has to be just so, and the sweet spot is limited. I just wanted to confirm that comb filtering would not be a problem as I had planned to use one of the Morel top mounted units at about 4khz, as thats where the WR125 starts to get directional, and the Morel maintains great spread past 10khz. If I get the right one I shouldnt even have to pad it. I'll be using an analogue electronic crossover with a 4th order slope, and graphic equalization to fine tune.
DIY Speaker
Folks, I appreciate all the good discussion regarding the x-over design I'm developing. I don't claim to be an expert when it comes to speaker design, and I am certainly willing to take any criticisms and/or recommendations more experienced individuals have.
The frequency response testing I performed was "on-axis" and with both drivers mounted in their final locations on the baffle and with the baffle installed on the enclosure. I am shooting for as close to a flat frequency response as possible for on-axis response. Tweeter and woofer measurements were both taken with the mic and enclosure in the same physical position to avoid phase issues and to compensate for driver off-sets.
The second order x-over on the woofer was needed because the woofer's output, while mounted on the baffle, is not flat up to 10/12k. My testing showed a big dip in the 4-7k region and then a big bump in the 9-11k region. To deal with these issues, I needed to take advantage of the roll-off beginning around 4k and then also reduce the output dramatically around 10k. The second order x-over does this nicely and results in a very smooth and natural roll-off while damping the 10k bump.
Testing the tweeter on the baffle shows that it also has some significant bumps in output, notably around 15k and also around 5k. Of note, the bump in output from the tweeter around 5k helps to compensate for the dip in the woofer output at around the same frequency.
Initial testing of the x-over shows the total combined output to be very flat in the mid-band from around 500 hz to around 5k and then the output rises steadily up to about 12k with a big bump around 15k. Listening tests also confirm that the tweeter is running a little "hot". I suspect that I need to increase the attenuation in my l-pad x-over circuit to regain a more natural balance above 5k. I may also choose to introduce a notch at around 15k to quell the big bump in output centered at that frequency. I will have to determine if this is necessary.
Overall, the system is extremely natural and clean sounding. Vocals are incredibly clear and detailed. I would say that both efficiency and power handling are low, but that was to be expected. Once this design is complete, I may consider building a TMM with the same drivers to help resolve some of the efficiency and power handling issues. I think this little mid-woofer would be really terrific as a dedicated midrange in a 3-way design with a properly tuned sealed enclosure.
When compared to my two way Scan Speak (7" carbon fiber/1" silk dome) setup, the WR125S/DX19 combination seems to image better and provide greatly superior midrange accuracy and detail although they do not provide nearly the same bass output as the SS 7" nor are they as "warm" sounding as the SS. This subjective opinion may be largely due to the current brightness from the DX19.
I will post again once the x-over design is finalized.
Regards,
Andrew
Folks, I appreciate all the good discussion regarding the x-over design I'm developing. I don't claim to be an expert when it comes to speaker design, and I am certainly willing to take any criticisms and/or recommendations more experienced individuals have.
The frequency response testing I performed was "on-axis" and with both drivers mounted in their final locations on the baffle and with the baffle installed on the enclosure. I am shooting for as close to a flat frequency response as possible for on-axis response. Tweeter and woofer measurements were both taken with the mic and enclosure in the same physical position to avoid phase issues and to compensate for driver off-sets.
The second order x-over on the woofer was needed because the woofer's output, while mounted on the baffle, is not flat up to 10/12k. My testing showed a big dip in the 4-7k region and then a big bump in the 9-11k region. To deal with these issues, I needed to take advantage of the roll-off beginning around 4k and then also reduce the output dramatically around 10k. The second order x-over does this nicely and results in a very smooth and natural roll-off while damping the 10k bump.
Testing the tweeter on the baffle shows that it also has some significant bumps in output, notably around 15k and also around 5k. Of note, the bump in output from the tweeter around 5k helps to compensate for the dip in the woofer output at around the same frequency.
Initial testing of the x-over shows the total combined output to be very flat in the mid-band from around 500 hz to around 5k and then the output rises steadily up to about 12k with a big bump around 15k. Listening tests also confirm that the tweeter is running a little "hot". I suspect that I need to increase the attenuation in my l-pad x-over circuit to regain a more natural balance above 5k. I may also choose to introduce a notch at around 15k to quell the big bump in output centered at that frequency. I will have to determine if this is necessary.
Overall, the system is extremely natural and clean sounding. Vocals are incredibly clear and detailed. I would say that both efficiency and power handling are low, but that was to be expected. Once this design is complete, I may consider building a TMM with the same drivers to help resolve some of the efficiency and power handling issues. I think this little mid-woofer would be really terrific as a dedicated midrange in a 3-way design with a properly tuned sealed enclosure.
When compared to my two way Scan Speak (7" carbon fiber/1" silk dome) setup, the WR125S/DX19 combination seems to image better and provide greatly superior midrange accuracy and detail although they do not provide nearly the same bass output as the SS 7" nor are they as "warm" sounding as the SS. This subjective opinion may be largely due to the current brightness from the DX19.
I will post again once the x-over design is finalized.
Regards,
Andrew
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